This project's objective is to maintain a breeding colony of macaca mulatta and provide pregnancies of known gestational age and term infants as well as immature animals to NICHD funded investigators. A secondary goal is to provide breeding stock for future research programs. The colony now includes a total of 243 animals, 113 adults in the indoor time-mated colony, 40 adults in the field cage, 28 juveniles and infants in the field cage, 59 animals in corn cribs and 2 infants/juveniles in the indoor colony currently being weaned. In 1994 the conception rate was 78.23%, Prenatal mortality rate from resorptions, abortions and stillbirths was 15.53%; Infant and adult mortality rates were 9.84% And 5.31%, Respectively. 36 Animals were loaned to investigators. 62.78% Of the adult animals are housed in the indoor time-mated breeding program. Surplus immature juveniles are reared in group cages outdoors until sexual maturity, then they are recycled into the indoor time-mated program. Continued efforts to enhance postnatal development via prenatal (intrauterine) treatment with epidermal growth factor (EGF) have been pursued; significant effects on premature infant lung and gut development has been shown by collaborating scientists. Additionally, transplantation of hematopoietic stem cells prenatally has proven effective for establishing stable nonhuman primate chimeras in the absence of graft-versus-host disease. Further applications of ultrasound have been applied and successfully eliminated the need for extensive surgical procedures. Studies designed to elucidate the mechanisms of action of epidermal growth factor (EGF) on lung in prematurely delivered rhesus monkeys suggest that it may be useful in the treatment of human babies with respiratory distress syndrome. Data also suggest that a combined egf/surfactant treatment regimen may be superior to treatment with surfactant alone.